The researchers of the Public University of Navarra (UPNA)in collaboration with scientific and technological teams from Italy, Poland and Colombia, have developed an optical biosensor capable ofdetect biomoleculessuch as proteins, DNA or viruses, in complex biological fluids, such as human serum, “with unprecedented precision and sensitivity”.
This device, which has been evaluated by detection immunoglobulin G (IgG)a type of antibody, at “extremely low” concentrations, can be used for early diagnosis of diseases“.
THE UPNA researchers involved in this work, published in the scientific journal “Advanced science”, are professors Ignacio del Villar Fernández and Ignacio R. Matías Maestro, researchers from the Institute of Smart Cities (ISC), and doctoral student Dayron Armas Peña.
The rest of the international team is composed of specialists from the Nello Carrara Institute of Applied Physics in Italy, the Warsaw University of Technology (Poland) and the National University of Colombia.
He biosensorsIt relies on a technology called biophotonics, which uses light to detect biomolecules. To create this sensor, the international team of researchers used nanofilms, which are extremely thin layers of material (a nanometer is one millionth of a millimeter) with special optical properties that are not observed in larger structures.
These nanofilms form what is called a one-dimensional photonic crystal. This crystal is integrated into an optical fiber, laterally polished so that the light interacts directly with the external environment, where the biomolecules are located.
So, when one of them approaches or adheres to the polished surface of the optical fiber, it affects the behavior of the light in the photonic crystal. These changes in light are detected by the sensor, allowing the presence and quantity of biomolecules to be identified.
THE “KEY TO SUCCESS”: HIGH SENSITIVITY AND PRECISION
One of the “key innovations” of this biosensor It involves choosing nanomaterials with high contrast in their refractive index (a measure of how light bends when it passes through a material) and low light losses.
This means that the sensor can detect even quantities very small biomolecules “with exceptional precision, crucial for medical applications.”
By realizing a balance between high sensitivity and a technical parameter known as bandwidth at half maximum (FWHM), the device “can clearly identify biomolecules without confusing them with other substances.”
This combination “significantly improves” the so-called factor of merit (FoM), an indicator of the overall performance of the device.
DETECT DISEASES AT THEIR EARLY STAGES
More precisely, the biosensor performance was evaluated by detecting the immunoglobulin G (IgG) antibody in human serum samples. The minimum concentration of a substance that the sensor can detect is called the limit of detection (LoD).
And the sensor developed by this international team with Participation in the UPNA achieved a record LoD of 70 attomolars (aM), an “extremely low concentration that is equivalent to detecting a single molecule among millions or having a single molecule in an ocean of a million billion liters of water “.
This level of sensitivity has “important implications for the early diagnosis of diseases”, since “allows you to find biomarkers in minimal quantities, when diseases are just beginning to develop.
